Three-Dimensional Microfluidic Collagen Hydrogels for Investigating Flow-Mediated Tumor-Endothelial Signaling and Vascular Organization
Three-Dimensional Microfluidic Collagen Hydrogels for Investigating Flow-Mediated Tumor-Endothelial Signaling and Vascular Organization
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DOI：
10.1089/ten.tec.2012.0731
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发表时间：
2014-01-01
影响因子：
3
通讯作者：
Rylander, Marissa Nichole
中科院分区：
文献类型：
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作者：
Buchanan, Cara F.;Voigt, Elizabeth E.;Rylander, Marissa Nichole
高渗透性肿瘤血管是导致肿瘤微环境内间质液压力升高和流动模式改变的原因。这些异常的流体动力学应力可能通过刺激肿瘤血管系统的内皮细胞的血管生成活性而促进肿瘤的发展。然而，目前尚不清楚剪切力在多大程度上影响肿瘤血管生成过程中的内皮组织或旁分泌信号。本研究的目的是开发一种三维（3D），在体外微流控肿瘤血管模型的肿瘤和内皮细胞在不同的流动剪切应力条件下的共培养。包埋在胶原蛋白水凝胶内的中央微通道用作单个新血管，通过该新血管引入肿瘤相关的流体动力学应力，并使用微粒图像测速法（-PIV）进行定量。这是第一次使用-PIV在肿瘤的代表性，3D胶原蛋白基质组成的圆柱形微通道，而不是平面几何形状，实验测量流速和剪切应力。结果表明，内皮细胞在微通道管腔上形成汇合的内皮，其在生理流动剪切应力下保持完整性。此外，该系统提供了下游分子分析能力，如定量RT-PCR所示，其中，肿瘤细胞在低流量条件下响应于与内皮细胞的共培养而显著增加促血管生成基因的表达。这项工作表明，在体外细胞培养模型的微流体可以承受一系列的生理流速，并允许定量测量壁剪切应力在流体-胶原蛋白界面使用PIV光流诊断，最终作为一个通用的平台，阐明肿瘤内皮细胞的串扰的流体力的作用。
Hyperpermeable tumor vessels are responsible for elevated interstitial fluid pressure and altered flow patterns within the tumor microenvironment. These aberrant hydrodynamic stresses may enhance tumor development by stimulating the angiogenic activity of endothelial cells lining the tumor vasculature. However, it is currently not known to what extent shear forces affect endothelial organization or paracrine signaling during tumor angiogenesis. The objective of this study was to develop a three-dimensional (3D), in vitro microfluidic tumor vascular model for coculture of tumor and endothelial cells under varying flow shear stress conditions. A central microchannel embedded within a collagen hydrogel functions as a single neovessel through which tumor-relevant hydrodynamic stresses are introduced and quantified using microparticle image velocimetry (-PIV). This is the first use of -PIV in a tumor representative, 3D collagen matrix comprised of cylindrical microchannels, rather than planar geometries, to experimentally measure flow velocity and shear stress. Results demonstrate that endothelial cells develop a confluent endothelium on the microchannel lumen that maintains integrity under physiological flow shear stresses. Furthermore, this system provides downstream molecular analysis capability, as demonstrated by quantitative RT-PCR, in which, tumor cells significantly increase expression of proangiogenic genes in response to coculture with endothelial cells under low flow conditions. This work demonstrates that the microfluidic in vitro cell culture model can withstand a range of physiological flow rates and permit quantitative measurement of wall shear stress at the fluid-collagen interface using -PIV optical flow diagnostics, ultimately serving as a versatile platform for elucidating the role of fluid forces on tumor-endothelial cross talk.